Assessment of Eutrophication Risks in Strategic Stagnant Ecosystems of the Marmara Basin via Modified Biodegradable Pollution Indices

Manyas - Uluabat eutrophication risk

Abstract

Lentic and enclosed aquatic systems are inherently vulnerable to organic enrichment and accelerated eutrophication due to their limited flushing capacities. Manyas and Uluabat Lakes, two ecologically significant freshwater resources in Northwestern Türkiye, serve as vital habitats and migratory corridors for diverse avian populations. Despite their high conservation status, these ecosystems face mounting pressures from intensified agricultural runoff, industrial effluents, and domestic wastewater. This research evaluates the eutrophication potential and organic pollution levels of Manyas Lake and Uluabat Lake utilizing a suite of Modified Biodegradable Contamination Indices (MBCI) based on regional environmental standards. During the winter of 2025, critical limnological parameters were measured to calculate the index values. The analytical outcomes revealed a significant divergence in the ecological health of the two systems; Manyas Lake demonstrated a substantially higher eutrophication risk compared to Uluabat Lake. According to the applied MBCI results, Manyas Lake was characterized as highly polluted with an advanced eutrophic status, whereas Uluabat Lake exhibited moderate pollution levels and a non-eutrophic character. These findings emphasize the urgent necessity for targeted management strategies to mitigate organic loading and preserve the ecological resilience of these strategic wetland habitats.